We enjoyed our stay at Dellago and can recommend the hotel. The staff was very friendly and the lake-views are magnificant. Also the restaurant is very nice and the food to be recommended.
The idea of the different styling in each room is very good but how it had been carried out (painting work, furniture etc.) is not highest level and is not 100% in line with the room rates.
Also only lake-side rooms (e.g. white & boxes) can be recommended as the others (e.g. Paul Klee) are very loud (street noise).
Conclusion: clearly to be recommended but a little over-priced